Characterization of Dualtropic Type C Retroviruses Isolated from Spontaneous Non-T Lymphomas of SJL/J(v+) MICE

Endogenous XC− viruses were isolated from non-T spontaneous lymphomas of SJL/J(v+) mice. These isolates were cloned by limiting dilution procedure and characterized for biological and immunological properties. At the electron microscope these isolates showed typical retrovirus type C morphology. Reverse transcriptase and immunofluorescence assays showed that these viruses were infectious for mouse and heterologous cell lines. Since some of the isolates induced cytopathic foci in mink lung cultures, they had properties similar to those described for other recombinant dualtropic viruses. Using a panel of monoclonal antibodies against gp 70 and p 15 (E) viral proteins, it was observed that the dualtropic XC− viral isolates had an antigenic profile different from that of SJL ecotropic XC+ virus.

Integration and Expression of Mcf-13 Provirus in Mcf-13-Induced Lymphomas

Polytropic viruses were isolated from 11 MCF-13-induced lymphomas using multiple infectious cycles on the mink lung and SC1 cell lines. The viruses were characterized by host range infectious properties and by biochemical properties using Cleveland's polypeptide mapping of the p30 and gp 70 viral proteins demonstrating identity in their biological properties with the MCF-13 lymphoma-inducing virus. Restriction enzyme analysis of the high molecular weight tumoral DNAs confirmed the presence of proviral sequences homologous to the inducing provirus in the lymphoma genomes indicating that MCF-13 MuLV has integrated in the cellular genome of the induced lymphomas.

A Bacterial Cause of Cancer: An Historical Essay

This article reviews the history of the discovery of microbes that increase the risk of cancer of some tissues with a special emphasis on the bacterium Helicobacter pylori and the role played by two Australian physicians, neither schooled in research, who had open minds about the shibboleth that mycobacteria (acid-fast organisms) can survive the acid environment of the stomach, but that other pathogenic bacteria cannot. They discovered one of the most important human pathogens, Helicobacter pylori, and showed it capable of inducing severe gastric inflammatory disease. Subsequently, others built on their observations and showed it capable of inducing two gastric neoplasms: carcinoma and lymphoma. The Oncologist 2017;22:542-548.

Lymphoma and Mycobacterium Avium Infection in a Ferret (Mustela Putorius Furo)

A 6-year-old, neutered male ferret presented with weight loss. Radiography revealed an enlarged liver and other abdominal masses. The ferret was euthanized, and at necropsy, the stomach wall was thickened, mesenteric lymph nodes were enlarged, and the liver contained multifocal tan nodules. Histopathology confirmed lymphoma and granulomatous inflammation in all affected organs. Acid-fast bacilli were present in the lesions and were confirmed to be Mycobacterium avium by PCR.

Spontaneous Herpesvirus saimiri lymphoma in owl monkeys

Three examples of spontaneous malignant lymphoma were observed in owl monkeys 23, 81, and 183 days after arrival in our laboratories. The pathological features of the disease were analogous to experimentally induced Herpesvirus saimiri lymphoma. H. saimiri was recovered from 2 animals (it was not attempted from one case) and one isolate was shown to reproduce characteristic H. saimiri malignant lymphoma. Each monkey originated in Peru in contrast to our usual source of owl monkeys which originate in Barranquilla, Colombia. Samples collected from owl monkeys in Peru did not reveal antibodies to H. saimiri nor were virus isolated from cocultured leukocytes. Squirrel monkeys in the same geographical location all carried H. saimiri. The observations indicate that H. saimiri lymphoma can occur as a spontaneous disease and that the virus can cross the same taxonomic lines in nature as in the laboratory.

Lymphoma caused by intestinal microbiota

The intestinal microbiota and gut immune system must constantly communicate to maintain a balance between tolerance and activation: on the one hand, our immune system should protect us from pathogenic microbes and on the other hand, most of the millions of microbes in and on our body are innocuous symbionts and some can even be beneficial. Since there is such a close interaction between the immune system and the intestinal microbiota, it is not surprising that some lymphomas such as mucosal-associated lymphoid tissue (MALT) lymphoma have been shown to be caused by the presence of certain bacteria. Animal models played an important role in establishing causation and mechanism of bacteria-induced MALT lymphoma. In this review we discuss different ways that animal models have been applied to establish a link between the gut microbiota and lymphoma and how animal models have helped to elucidate mechanisms of microbiota-induced lymphoma. While there are not a plethora of studies demonstrating a connection between microbiota and lymphoma development, we believe that animal models are a system which can be exploited in the future to enhance our understanding of causation and improve prognosis and treatment of lymphoma.

Autologous tumor cells engineered to express bacterial antigens

Cancer immunotherapies are emerging as promising treatment modalities in the management of the disease. As a result, cancer vaccines are considered to be immensely crucial in preventing recurrence, a well-known nemesis in cancer patients because they have the potential to activate memory antitumor immunity. Due to poor antigenicity and self-tolerance, most tumor antigens require interventional vaccine therapies to provide an adequate "danger" signal to the immune system in order to activate a robust, clinically meaningful antitumor immunity. It has been postulated that this requirement may be achieved by providing bacterial and/or viral immunogens to prime this type of immune response. Briefly, we provide here a method of transfecting whole tumor cells with plasmid DNA encoding an immunogenic bacterial protein such as Emm55, which was derived from Streptococcus pyogenes (S. pyogenes). Subsequent inactivation of the transfected cells by irradiation (100 Gray) prevents replication. This type of whole-cell vaccine, e.g., ImmuneFx™, has demonstrated activity in a murine neuroblastoma model, in canine lymphoma patients with naturally occurring disease, and in many cancer types in companion animals. The protocols described in this chapter provide the necessary materials and methodologies to manufacture such a vaccine.

Rare case of Helicobacter pylori-related gastric ulcer: Malignancy or pseudomorphism?

Helicobacter pylori (H. pylori) is a pathogen and the most frequent cause of gastric ulcers. There is also a close correlation between the prevalence of H. pylori infection and the incidence of gastric cancer. We present the case of a 38-year-old woman referred by her primary care physician for screening positron emission tomography-computed tomography (PET-CT), which showed a nodular strong accumulation point with standardized uptake value 5.6 in the gastric fundus. Gastroscopy was then performed, and a single arched ulcer, 12 mm in size, was found in the gastric fundus. Histopathological examination of the lesion revealed chronic mucosal inflammation with acute inflammation and H. pylori infection. There was an obvious mitotic phase with widespread lymphoma. Formal anti-H. pylori treatment was carried out. One month later, a gastroscopy showed a single arched ulcer, measuring 10 mm in size in the gastric fundus. Histopathological examination revealed chronic mucosal inflammation with acute inflammation and a very small amount of H. pylori infection. The mitotic phase was 4/10 high power field, with some heterotypes and an obvious nucleolus. Follow-up gastroscopy 2 mo later showed the gastric ulcer in stage S2. The mucosal swelling had markedly improved. The patient remained asymptomatic, and a follow-up PET-CT was performed 6 mo later. The nodular strong accumulation point had disappeared. Follow-up gastroscopy showed no evidence of malignant cancer. H. pylori-associated severe inflammation can lead to neoplastic changes in histiocytes. This underscores the importance of eradicating H. pylori, especially in those with mucosal lesions, and ensuring proper follow-up to prevent or even reverse early gastric cancer.

[Histopathologic and immunohistochemic changes in Helicobacter pylori colonised gastric mucosa]

Helicobacter pylori (H. pylori) colonize gastric mucosa causing both inflammatory changes, premalignant lesions and malignant tumors, including gastric lymphoma and carcinoma. In this study, our propose was to evaluate the histopathological changes corellated with immunohistochemical results demonstrating the types of cellular infiltration and proliferative activity of gastric mucosa infected with H. pylori.

MATERIAL AND METHOD

Gastric endoscopic examinations was performed in 468 patients with anti-H. pylori antibodies and dispeptic phenomena. Snippets harvested endobiopsic stomach were fixed in formalin and processed by paraffine inclusion. Histological sections were stained with hematoxylin-eosine and Giemsa. In 65 cases of endobiopsic fragments (36 deep chronic gastritis with intestinal metaplasia, glandular atrophy and intraepithelial neoplasia and 29 carcinomas) immunohistochemical reactions were performed by applying reagents for evidence of H. pylori colonies, of T lymphocytes (CD3) and macrophages (CD68) and Ki-67 reagent for proliferating nuclear antigen labelling.

RESULTS

Endobiopsic specimen found in all H. pylori or by Giemsa staining or by anti-H. pylori antibodies when they were in small numbers. Histologically, were diagnosed : 463 superficial and deep chronic gastritis associated with premalignant lesions, 29 carcinomas, 2 non-Hodgkin's lymphoma and an adematous polyp. Immunohistochemically, inflammatory infiltrate consisted of numerous T lymphocytes, macrophages and lymphoid follicles. Foveolar cell nuclei, in areas of intraepithelial neoplasia and carcinomatous cells were intensely stained with Ki-67, demonstrating increased proliferation.

CONCLUSIONS

In gastric infection with H. pylori, inflammatory infiltrat is composed of abundant macrophages and T lymphocytes. Ki-67 was absent or minimal in chronic gastritis, while in areas of intraepithelial neoplasia was positive in both foveolar and coating epithelium. Anti-H. pylori antibodies in human serum remains one of the simplest methods to detect H. pylori, therefore it plays an important role in practice. Medical eradication of bacteria may cancel inflammatory changes, metaplasia and proliferation of gastric mucosa and thus it prevents the cascade of carcinogenesis.

Carcinogenesis and infection with Helicobacter pylori

It was accepted several years ago that, in the carcinogenesis process of human cancers, biologic agents, especially the viruses, are playing an etiologic role. This is the case of lymphomas (retroviruses), hepatocarcinoma (hepatic viruses) and cervical carcinoma (papilloma viruses). Helicobacter pylori is the first bacteria recognized as a first class carcinogen for gastric cancer. Nevertheless, comparing with the most validated human carcinogens, the activity of H. pylori is very little studied. As a consequence, at this moment, in its case, explanation of carcinogenesis mechanism is more or less hypothetical.

Identification of Chlamydia trachomatis in a patient with ocular lymphoma

Accumulating evidence suggests that infectious agents may play a role in ocular adnexa lymphomas (OALs) of MALT-type [1-4]. In particular, Chlamydia psittaci, the causative agent of psittacosis, has been detected by PCR in most patients from Italy or isolated eastern Asiatic countries with OALs in absence of other Chlamydia species [4-8]. These patients have also been shown to have a complete or partial response to doxycycline, recognized to be a cheap and safe treatment in these patients [5,6]. In contrast, OAL patients from other geographic areas and with different genetic background were found to be negative for C. psittaci DNA or had a quite variable response to antibiotic treatment, assuming that this pathogen might not play a ubiquitous role in OALs and that bacterial infection is not associated with OAL [8-12].

Tigecycline use in cancer patients with serious infections: a report on 110 cases from a single institution

Tigecycline, the first in a new class of glycylcyclines, has been approved for the treatment of complicated skin and skin structure and intraabdominal infections in adults. However, clinical data on its safety and effectiveness in cancer patients are lacking. We reviewed the records of all cancer patients treated with tigecycline for more than 48 hours between June 2005 and September 2006 at our institution and identified 110 consecutive cases (median age, 58 yr; range, 18-81 yr). We collected data on demographics, cancer type, tigecycline indication, microbiologic characteristics, side effects, and outcome. Sixty-four (58%) patients had hematologic malignancies; 27 patients had undergone hematopoietic stem cell transplantation. Thirty-one (28%) patients had neutropenia, and 62 (56%) were in the intensive care unit at the start of therapy. Most patients (106 [96%]) received tigecycline as a second-line agent (after not responding to other broad-spectrum antibiotics), and 101 (92%) received it in combination with an antipseudomonal drug. The mean duration of therapy was 11 days (range, 3-35 d). Sixty-six (60%) patients received tigecycline for refractory pneumonia, 19 (17%) had bacteremia, 9 (8%) had intraabdominal infections, and 7 (6%) had complicated skin and soft tissue infections. Fifty (45%) patients had microbiologically documented infections, and the remaining patients had negative cultures at the start of therapy.An overall clinical response was noted in 70 (64%) patients. More clinical responses were seen in patients with bacteremia than in those with pneumonia (79% vs. 51%; p = 0.029). Patients with microbiologically documented infections had significantly higher clinical response rates than patients with non-microbiologically documented infections (73% vs. 55%; p = 0.047). Forty (36%) patients did not respond to treatment; 36 of these patients died of active infection during tigecycline therapy. Patients with pneumonia had a significantly higher mortality rate than patients with bacteremia (44% vs. 16%; p = 0.026). During the 60 days of follow-up from the date of clinical response, patients with pneumonia had significantly shorter survival durations than patients with other infections. Of the 42 patients who were not on antiemetics or ventilator support at the start of tigecycline therapy, 2 (5%) experienced mild nausea, and 1 (2%) experienced nausea and vomiting. Only 4 (4%) patients overall experienced diarrhea during tigecycline therapy, all of whose stools were negative for Clostridium difficile toxin. No serious adverse events related to tigecycline use were identified. The combination of tigecycline and an antipseudomonal drug may be appropriate for treating refractory infections and multidrug-resistant organisms in cancer patients, including hematopoietic stem cell transplant recipients. Patients with refractory pneumonia had a relatively low clinical response rate in our study.

[The gastric MALT lymphoma. An unforeseen model for studying the pathogenesis of the lymphomas]

MALT lymphoma is a low-grade lymphoma originating from the mucosa associated lymphoid tissue. It is the third most frequent non-Hodgkin B-cell lymphomas. One third of the cases is primary gastric. The causal association between Helicobacter pylori infection and gastric MALT lymphoma is proved by numerous clinical and experimental studies. The most dramatic evidence supporting a pathogenetic role for H. pylori in gastric MALT lymphoma is remission of the tumour following eradication with antibiotic therapy. However, the evolution of a H. pylori infection towards lymphoma is an exceptional event which takes place probably due to the concurrence of host, environmental and bacterial strain factors. Gastric MALT lymphoma is currently the only malignant neoplasia that can be cured by a simple antibiotic therapy. In early stage cases the Helicobacter pylori eradication is the first line therapy as it obtains stable remissions in most of the cases. Surgical treatment of this disease has been completely abandoned. The role of chemio and radiotherapy is limited to the few cases non-responders to the antibiotic therapy. This paper offers a wide and updated review of the literature about gastric MALT lymphoma. Practical points for the clinical management are also given, in keeping with the European Guidelines that will be shortly published.

Staphylococcus aureus bacteremia in patients with hematological malignancies and/or agranulocytosis

A total of 6,253 cases of Staphylococcus aureus bacteremia, including 274 (4.4%) endocarditis cases, were registered in Denmark in the period 1975-1984. Patients with hematological malignancies and/or agranulocytosis accounted for 479 of the bacteremia cases. The incidence of endocarditis in this group of patients was only 0.4% as compared to 4.7% in other patients with staphylococcal bacteremia (p less than 0.01). The lower incidence of endocarditis complicating bacteremia in these patients may justify a shorter course of therapy than usually recommended for suspected endocarditis. Patients with hematological malignancies and other patients with agranulocytosis had a higher mortality (49 and 46%, respectively) than other patients with S. aureus bacteremia (33%). The highest mortality was found in patients with multiple myeloma (71%, p less than 0.01), the lowest in patients with acute lymphocytic leukemia (28%, p less than 0.01). The higher mortality in these patients may indicate that empiric antibiotic regimens in granulocytopenic patients should include a specific anti-staphylococcal agent.

[Bacteremia in hematological malignant disorders]

BACKGROUND

Bacteremia frequently complicates cytostatic treatment of hematological malignancies. Initial antibiotic treatment is chosen empirically before the results of cultures are available. Rational choices depend on updated knowledge of microbial resistance patterns. We have examined microorganisms in blood cultures over a 10-year period and compared them with the preceding 5-year period.

MATERIAL AND METHODS

We analyzed isolates from blood cultures in patients with a hematological malignant disorder treated in the Hematology Unit, St. Olavs Hospital during the years 1995 - 2005.

RESULTS

We found 373 isolates and 322 episodes of bacteremia in 225 patients. Most patients had acute leukemia or myeloma, with neutropenia after cytostatic treatment. The dominating pathogens were Escherichia coli (20 %), coagulase-negative staphylococci (13 %) and alpha-haemolytic streptococci (10 %). Enterococcus infections seem to occur more frequently and were associated with a high mortality. Gram-negative organisms constituted 48 % and gram-positive organisms 48 % of the isolates. About 3 / 4 of the patients had infections with penicillin-resistant bacteria. There was a low prevalence of organisms resistant to aminoglycoside. Acute leukemia patients with bacteremia had a 30-days all-cause mortality of 10.3 %.

INTERPRETATION

We found small changes in the pattern of pathogens and antibiotic resistance over time. The rates of antibiotic resistance were favorable compared to other European countries. The mortality rate seems to be unchanged and acceptable. Penicillin G and aminoglycoside can still be considered as first-line treatment for suspected bacteremia in neutropenic patients in Norway.

[Gastric lymphoma. Morphological and immunohistochemical study]

Most of extranodal lymphomas are localized in gastrointestinal tract, gastric lymphoma representing more than 50% of them. The role that Helicobacter pylori (H. pylori) plays in pathogenesis of gastric lymphoma has changed the therapeutic approach.

AIMS

Description of morphological features and immunohistochemical pattern of gastric lymphomas from patients admitted in University Hospital "Sf. Spiridon" Iaşi.

MATERIAL AND METHODS

Thirty four gastric lymphomas were investigated using routine histopathological technics and immunohistochemical staining based on a large panel of antibodies: CD3, CD5, CD20, CD79á, CD23, CD30, cyclin-D1, BCL2, BCL6, ALK1, Ki67, CK-cocktail, anti-H. pylori.

RESULTS

All gastric lymphomas were localized in the antrum, most of them being solitary and large-sized tumors. Ninety-seven percent were B-cell lymphomas, 41.17% were mucosa-associated lymphatic tissue lymphomas (MALT lymphomas), and the remaining were high grade lymphomas. Only one case was classified as peripheral T-cell lymphoma. Cytokeratin cocktail immunostaining improved the detection of typical lymphoepithelial lesions, which characterized exclusively the MALT lymphomas. The sensibility for H. pylori detection in gastric lymphoma cases was increased by 22% using anti-H. pylori antibodies.

CONCLUSIONS

Immunohistochemistry is a diagnostic method for gastric lymphomas, being useful in identification of lymphoepithelial lesions, detection of H. pylori infection, and is mandatory for lymphomas classification according to WHO criteria.

Primary gastrointestinal lymphoma--a clinicopathologic study

Gastrointestinal tract is the most common site for the development ofextra nodal lymphoma. This study was done to analyze clinical and pathological features as well as the treatment outcome of this disease. We carried out analysis of25 cases of primary gastrointestinal (GI) lymphomas during period from March 2001 to February 2003 at Gujarat Cancer & Research Institute. Out of 25 cases of primary GI lymphoma, nine cases of gastric lymphoma, nine cases of small intestinal lymphoma and seven cases of large intestinal lymphoma were identified. A male to female ratio of 2.6:1 was observed. Peak incidence was observed infirst and second decades of life (range 4-63 years). Abdominal pain and abdominal lump were the two most common presenting symptoms. Diffuse large B-cell type and Burkitt's lymphoma were the most common histologic variants, accounting for equal proportions (36% each). All the patients were treated with either surgery alone or in combination of surgery, chemotherapy and radiotherapy depending on the site, stage and histology. Anti H-pylori kit was used in early stage GI maltomas. 18 cases of GI lymphoma were evaluable, and out of these, 66.6% (11 cases) attained complete remission with a median follow up time of 12 months. The disease free survival was 50% (9 cases), and the overall survival was 72.2% (13 cases). In conclusion, although there are considerable therapeutic controversies, surgery with adjuvant chemotherapy and radiotherapy yield good survival. Clinical and histopathologic characteristics and prognosis of our cases with primary gastrointestinal lymphoma were usually similar to the cases in western countries with some differences in the incidence and histologic subtypes.

Chlamydia psittaci in ocular adnexal lymphoma: Japanese experience

We searched for the Chlamydia psittaci DNA the touchdown enzyme time release PCR (TETR-PCR) in 23 specimens from 21 patients with ocular adnexal lymphoproliferative disorders, including 12 patients with MALT lymphoma to identify C. psittaci infection. Southern hybridization of the PCR product using the C. psittaci-specific probe failed to detect C. psittaci, although three samples appeared to be positive by ethidium bromide staining. This indicates that technical approach for detecting C. psittaci infection in ocular adnexal lymphoma might be an essential in disclosing this association.

Association of gastroduodenal disease phenotype with ABO blood group and Helicobacter pylori virulence-specific serotypes

AIMS

To investigate the prevalence of Helicobacter pylori infection in Lebanon and the association between virulence factors (cytotoxin-associated gene A and vacuolating cytotoxin gene A), ABO blood groups, and disease phenotype.

METHODS

One hundred and thirty symptomatic patients with H. pylori-associated endoscopic findings and 104 healthy male donors (age range 18-55) were evaluated. Both, patients and donors underwent ABO blood typing and Western blot for cytotoxin-associated gene A and vacuolating cytotoxin gene A.

RESULTS

The prevalence of H. pylori infection in healthy donors is 68.3%. Type I (cytotoxin-associated gene A- and vacuolating cytotoxin gene A-positive) was the predominant phenotype in all groups, though significantly less common in the asymptomatic population (46.5%) than in patients with benign disease (71.4%, p<0.01) or malignancy (71.6%, p<0.05). Type II (cytotoxin-associated gene A- and vacuolating cytotoxin gene A-negative) and vacuolating cytotoxin gene A-only strains were more common in the asymptomatic cohort. Overall, 35.2% of asymptomatic individuals and 10.8% of patients with benign disease were cytotoxin-associated gene A-negative (p<0.01). There was no significant association between immunoserotypes, ABO groups or benign gastroduodenal disease. All gastric malignancies (lymphoma and adenocarcinoma) were cytotoxin-associated gene A-positive but this was not significantly different from patients with benign disease. We found a higher prevalence of blood group A in patients with gastric malignancy than in the general population [47.6% versus 25%, p=0.037; RR=2.73 (1.04-7.16; 95% CI)].

CONCLUSIONS

The seroprevalence of H. pylori is moderately high in Lebanon. Phenotypic classification identifies a higher prevalence of Type I in symptomatic patients. A significant relationship between infection with a cytotoxin-associated gene A-positive strain in blood type A patients and the risk of gastric malignancy was noted.

Clinical and endoscopic presentation of primary gastric lymphoma: a multicentre study

BACKGROUND

Although the stomach is the most frequent site of intestinal lymphomas, few data are available on both clinical endoscopic presentation of gastric lymphoma and possible differences between low-grade and high-grade lymphomas.

METHODS

Clinical, histological and endoscopic records of consecutive patients with primary low-grade or high-grade lymphoma diagnosed were retrieved. Symptoms were categorized as 'alarm' or 'not alarm'. The endoscopic findings were classified as 'normal' or 'abnormal'.

RESULTS

Overall, 144 patients with primary gastric lymphoma were detected, including 74 low-grade and 70 high-grade lymphoma. Alarm symptoms, particularly persistent vomiting and weight loss, were more frequently present in patients with high-grade lymphoma than in those with low-grade lymphoma (54% vs. 28%; P = 0.002). Low-grade lymphomas presented as 'normal' appearing mucosa (20% vs. 0%; P = 0.0004) or petechial haemorrhage in the fundus (9% vs. 0%; P = 0.02) more frequently than high-grade lymphomas, being also more often confined to the antrum (47% vs. 27%, P = 0.03) and associated with Helicobacter pylori infection (88% vs. 52%, P < 0.0001). On the contrary, high-grade lymphomas presented more commonly as ulcerative type (70% vs. 52%; P = 0.03), being also more frequently diagnosed in stage >I when compared with low-grade lymphomas (70% vs. 21%, P < 0.0001).

CONCLUSIONS

The overall prevalence of alarm symptoms is quite low and may be absent in more than 70% of patients with low-grade lymphoma.

A past history of gastric ulcers and Helicobacter pylori infection increase the risk of gastric malignant lymphoma

Helicobacter pylori (H. pylori) is a causative agent for peptic ulcers as well as some types of gastric lymphoma; however, the relationship between a peptic ulcer history in combination with H. pylori infection and the risk of gastric lymphoma has not been fully evaluated. To examine this point, we conducted a case-control study with 645 patients histologically diagnosed as having malignant lymphomas and 3225 non-cancer controls. Plasma H. pylori IgG status was assessed for subgroups for which blood samples were available (116 cases and 114 controls). An association with a history of gastric, but not duodenal ulcers was found for gastric lymphoma [odds ratio (OR) = 5.41, 95% confidence interval (CI): 3.12-9.39]. In the examination according to histological subtype, the OR was high for both gastric mucous-associated lymphoid tissue (MALT) lymphoma (OR = 5.54, 95% CI: 2.56-12.01) and diffuse large B-cell lymphoma (DLBCL) (OR = 7.23, 95% CI: 2.62-19.90). In the analysis of H. pylori antibody, the risk of total gastric lymphoma was associated with H. pylori infection (OR = 5.34, 95% CI: 1.42-20.05). A high prevalence of H. pylori infection was also found for both gastric MALT lymphoma (8 out of 10: 80.0%) and DLBCL (8 out of 9: 88.9%). Further, in subgroup analysis of subjects with H. pylori infection, gastric ulcer history, but not duodenal ulcer history was associated with the risk of gastric lymphoma (OR = 4.15, 95% CI: 1.02-16.89). In conclusion, we found a positive association with a past history of gastric ulcer and H. pylori infection for gastric lymphoma, while duodenal ulcer history was no association. These results suggested the risk of gastric lymphoma increased by interaction between H. pylori infection and gastric ulcer history. Further studies are warranted.

Mycotoxigenicity of clinical and environmental Aspergillus fumigatus and A. flavus isolates

Clinical isolates of fifty strains of A. fumigatus and 30 strains of A. flavus from immmunocompromised patients from the hematological unit were analyzed for mycotoxin production and compared with the same number of environmental isolates (from soil, compost, and air). Only 9 (18%) strains of A. fumigatus produced gliotoxin in a mean concentration 2.22 mg mL-1 (range 0.5-5 mg mL-1). Aflatoxin B1 was detected in 7 (23%) isolates (range from 0.02 to 1.2 mg L-1) and aflatoxin G1 in one (3%) of clinical A. flavus isolates (0.12 mg L-1). In the group of environmental isolates, 11 (37%) were positive for aflatoxin B1 production (range from 0.02 to 1.2 mg L-1) and one for aflatoxin G1 (0.02 mg L-1). Bioautoantibiogram ("bioassay in situ") on TLC plates against Bacillus subtilis NCTC 8236 showed that only gliotoxin-producing strains have bactericidal activity of Rf values corresponding to gliotoxin. The secondary-metabolite profiles of clinical and environmental A. fumigatus and A. flavus isolates were homogeneous, except for gliotoxin production, which was detected only in the group of clinical isolates of A. fumigatus (18%).

Helicobacter pylori and the pathogenesis of gastroduodenal disease: Implications for the management of peptic ulcer disease

The discovery of Helicobacter pylori has changed our understanding of the pathophysiology of peptic ulcer disease. An estimated one billion people harbour the organism worldwide but the highest prevalence is found in developing countries with up to 80% of people infected. The most favoured modes of transmission are faeco-oral and oral-oral. The mechanisms of H pylori-induced gastroduodenal disease include the provocation of local inflammatory reaction with the release of toxic cytokines, elevation of gastrin concentration and cytotoxic epithelial injury from the activity of urease and other enzymes produced by the bacterium. However, a large proportion of infected persons have no disease or are asymptomatic thereby suggesting that there may be other factors apart from H pylori infection necessary for ulcer formation. The simple finger prick test, a variant of serology and the newly developed ELISA-based Faecal Antigen Test hold the ace for large-scale epidemiological studies. The eradication of H pylori is now a very important goal of treatment of gastric and duodenal ulcers. Most H pylori eradication regimens combine anti-secretory agent, usually a proton pump inhibitor or H2-receptor antagonist and two antibiotics (usually, Clarithromycin and Amoxycillin or Metronidazole). Emergence of antibiotic resistance is worrisome but a quadruple therapy that incorporates bismuth may be used if the triple therapy fails.

Risk of lymphatic or haematopoietic cancer mortality with occupational exposure to animals or the public

BACKGROUND

Occupational exposure to animals or the public could result in exposure to infectious agents, which may play a role in the aetiology of lymphohaematopoietic (LH) cancers.

AIMS

To conduct a population based, case-control study of death certificate data from 1984 to 1998 in 24 US states in order to evaluate the risk of mortality from LH neoplasms associated with occupational exposure to animals or the public.

METHODS

Cases were selected as those with an underlying cause of death of non-Hodgkin's lymphoma (NHL, n = 72,589), Hodgkin's disease (HD, n = 5479), multiple myeloma (n = 35,857), or leukaemia (n = 68,598); 912 615 controls were randomly selected from all remaining deaths, frequency matched on age, sex, race, and geographic region.

RESULTS

Occupational exposure to animals was associated with modest increased risks of mortality from all four LH cancers; these associations varied by region. Occupational exposure to the public was associated with only negligible increased risk with LH cancer outcomes. Occupations involving animal exposure were predominantly agricultural, and the risks associated with employment in the livestock industry exceeded the corresponding risks associated with the crop industry for all outcomes except HD.

CONCLUSIONS

Increased risks of NHL, HD, multiple myeloma, and leukaemia were associated with occupations that involved animal exposure. Regional differences in risk imply that the risks may be associated with exposure to specific livestock or farming practices. However, these associations may be confounded by other farming related exposures, such as pesticides. Because the use of death certificates to classify occupation may result in misclassification during aetiologically relevant time periods, these hypotheses should be further explored in studies with detailed information on lifetime occupation.

Community clusters of childhood leukemia and lymphoma: evidence of infection?

Information suggesting that infection may be an underlying cause of childhood leukemia and lymphoma includes the occasional appearance of cases in time-space clusters within communities and increased incidence after communities experience marked population influxes (population mixing). Among 50 clusters involving cases of childhood leukemia and lymphoma investigated in the United States in 1961-1977, eight showed suggestive evidence of underlying infectious causation. In seven of the eight communities, case occurrence was associated with the attendance of patients or their siblings at particular schools or with family participation in particular church groups. In five, rapid population growth had occurred. Other findings included the possible association of cases with unusual patterns of infectious disease (rheumatic illness in one community, chickenpox in another) and with other childhood diseases, including other forms of childhood cancer. In one community, two cases of Burkitt's lymphoma occurred at the same time, and a third case arose 3 years later in boys living in a newly developing neighborhood. Such community observations support the need for continued biologic research regarding the possible role of infectious agents in childhood leukemia and lymphoma.

[Antibiotic resistance in Helicobacter pylori and molecular methods for the detection of resistance]

Helicobacter pylori which is the major agent causing peptic ulcer, gastric cancer and gastric lymphoma, is identified as a class I carcinogen. Invasive and non-invasive tests have been used in the diagnosis of H. pylori infection. Clarithromycin resistance in H. pylori strains is increasing nowadays, thus leading to failures in eradication therapy. Fluorescence in situ hybridization (FISH) method which can simultaneously detect the presence of H. pylori and clarithromycin resistance is a non-culture dependent molecular technique. In this review article the prevalence and clinical outcome of antibiotic resistance in H. pylori, molecular mechanisms of the resistance and molecular methods to detect the resistance, with priority of FISH technique have been discussed.

Necrotizing vasculopathy of the CNS: case report

A 62-year-old man with progressive cerebellar and brainstem dysfunction had gadolinium-enhancing lesions in basal ganglia and occipital lobe on MRI suggestive of primary CNS lymphoma (PCNSL). The patient, who had been treated with high-dose steroid hormones for several months, developed respiratory failure and expired before a histological diagnosis could be obtained. The postmortem examination showed Pneumocystis cariniiwas the cause of death. Pathology of the brain showed a necrotizing vasculopathy affecting the white matter of the cerebrum and cerebellum with involvement of the basal ganglia and the periventricular gray matter. Other organs such as liver, lung, and kidneys were spared. Necrotizing vasculopathy is a novel entity that should be considered in the differential diagnosis of PCNSL.

Bifidobacterium longum as an oral delivery system of endostatin for gene therapy on solid liver cancer

To overcome difficulties that hampered widespread application of a specific delivery system in cancer gene therapy and to inhibit the growth of solid liver cancer, we utilized a strain of Bifidobacterium longum as a delivery system to transport an endostatin gene that can inhibit growth of tumor. The B. longum strain with the endostatin gene (B. longum-En) was taken orally by tumor-bearing nude mice through drencher preparation. The results showed that B. longum-En could strongly inhibit the growth of solid liver tumor in nude mice and prolong the survival time of tumor-bearing nude mice. Furthermore, tumor growth was inhibited more efficiently when the B. longum-En treatment included selenium. Enriching the B. longum-En treatment with selenium improves the activity of NK and T cells and stimulates the activity of IL-2 and TNF-alpha in BALB/c mice. These results suggest that B. longum may be a highly specific and efficient vector for transporting anticancer genes in cancer gene therapy.

The relation of Helicobacter pylori to gastric adenocarcinoma and lymphoma: pathophysiology, epidemiology, screening, clinical presentation, treatment, and prevention

Helicobacter pylori infection may be the most common chronic bacterial infection worldwide; however, the prevalence varies between countries and is usually linked to socioeconomic conditions. Gastric cancer is one of the most frequent cancers in developing countries and usually about the seventh most common in developed countries. This article explores the relation of H. pylori to gastric adenocarcinoma and lymphoma. The pathophysiology, epidemiology, screening, clinical presentation, treatment, and prevention are discussed.

Pleomorphic mammalian tumor-derived bacteria self-organize as multicellular mammalian eukaryotic-like organisms: morphogenetic properties in vitro, possible origins, and possible roles in mammalian `tumor ecologies'

Highly pleomorphic bacteria have regularly been isolated from mammalian tumors and leukemic bloods. Here, it is shown that highly pleomorphic, cell-wall deficient bacteria derived from a mammalian tumor self-organize in vitro into mammalian tissue-like morphogenetic patterns consisting of multicellular tissue-like sheets and capillary-like networks. It is proposed that these pleomorphic mammalian tumor-derived (MTD) bacteria, during morphogenesis, express mammalian tissue morphogenesis-related genes that were acquired through eukaryote-to-prokaryote DNA transfer. Similar pleomorphic MTD bacteria might play important roles as symbiotic multicellular mammalian eukaryotic-like organisms in mammalian 'tumor ecologies' that include malignant and nonmalignant mammalian eukaryotic cells. From a mammalian tumor ecology perspective, eradication of tumors in some mammalian hosts may depend upon the elimination of pleomorphic MTD bacteria self-organized as symbiotic multicellular mammalian eukaryotic-like organisms. Further investigations of the extraordinary mammalian eukaryotic-like multicellularity of these bacteria may yield fundamental insights into the evolution of multicellularity and multicellular development and may challenge basic assumptions regarding cellular evolution.

Regression of rectal mucosa-associated lymphoid tissue lymphoma but persistence of Helicobacter pylori infection of gastric mucosa after administration of levofloxacin: report of a case

PURPOSE

Several articles have reported regression of rectal lymphoma of mucosa-associated lymphoid tissue after anti- Helicobacter pylori therapy. It remains unclear, however, whether lymphoma of rectal mucosa-associated lymphoid tissue is related to Helicobacter pylori infection.

METHODS

A 60-year-old woman visited our hospital with a complaint of hematochezia. On colonoscopy a pale, ulcerated protrusion approximately 3.5 cm in diameter was found in the rectum. Pathologic diagnosis of a biopsy specimen was low-grade mucosa-associated lymphoid tissue lymphoma. The patient received a ten-day course of levofloxacin, and the cycle was repeated three times over seven months.

RESULTS

Although persistence of Helicobacter pylori infection was confirmed, the tumor regressed completely.

CONCLUSION

Our findings in this case suggest that rectal lymphoma of mucosa-associated lymphoid tissue may be related to unknown microorganisms other than Helicobacter pylori. Levofloxacin may be effective for treatment of rectal lymphoma of mucosa-associated lymphoid tissue regardless of Helicobacter pylori infection.

Anemia Associated With ’Candidatus Mycoplasma haemominutum’ in a Feline Leukemia Virus-Negative Cat With Lymphoma

’Candidatus Mycoplasma haemominutum,’ previously known as the small form of Haemobartonella felis (California species), is a hemotrophic parasite found on erythrocytes of infected cats. Although fleas are potential vectors, confirmatory studies are lacking. Healthy cats infected with ’Candidatus Mycoplasma haemominutum’ generally do not have clinically significant anemia, but concurrent disease or immune suppression may predispose a cat to develop a life-threatening anemia, such as in the case reported here.

Childhood cancer in developing countries

The problem of childhood cancer cannot be evaluated separately from developmental levels and states of health of the countries. Rapid increase in population, poverty, poor hygiene, lack of education, and multitude health problems impede the development of pediatric oncology and success of the management of childhood cancer in developing countries. More than 85% pediatric cancer cases occur in developing countries that use less than 5% of world resources. The rate will exceed 90% in the next two decades, due to the increase of youth population in favor of developing countries. Incidence rates, pathology, and clinical characteristics of various cancers seem different in developing and developed countries. Different environments, life styles, dietary habits, and hygienic conditions are the main reasons for those differences. Unprecedented changes in diagnostic techniques, treatment methods and supportive care have occurred during the last decades. Consequently, management has improved and the mortality rates have decreased. Most of the children with cancer living in developing countries could not profit from those advances in pediatric oncology because of the cost.

Systemic humoral anti-Helicobacter pylori immune response in patients with gastric malignancies and benign gastroduodenal disease

BACKGROUND/AIMS

Helicobacter pylori elicits a strong local and systemic humoral immune response, but it is not able to eliminate bacteria. Immune response may be important for the course of infection that may lead to different gastroduodenal disease. In order to investigate differences in systemic humoral immune response between patients with different gastroduodenal diseases, we conducted clinical and serological studies.

METHODOLOGY

From 1999 to 2001 we enrolled 80 patients with dyspeptic symptoms: 26 with gastritis, 12 with duodenal ulcer, 29 with gastric cancer and 13 with gastric lymphoma. In all patients during diagnostic work-up we performed ELISA test with Helicobacter pylori-specific IgG and IgA. We investigated difference in stimulation of different immunoglobulin classes in patients with different gastroduodenal diseases, particularly benign and malignant. We estimated significance of differences with Mann-Whitney and Fisher exact probability test.

RESULTS

All patients enrolled in the study were seropositive. Patients with gastritis had statistically significant higher level of IgG than patients with gastric cancer (p=0.0001), and gastric lymphoma (p=0.006). Patients with duodenal ulcer had statistically significant higher level of IgG than patients with gastric cancer (p=0.02), and gastric lymphoma (p=0.046). IgA level was significantly higher in patients with gastritis than in patients with gastric cancer (p=0.03). IgA>IgG ratio was significantly more frequent in patients with gastric cancer and gastric lymphoma than in patients with gastritis and duodenal ulcer (p=0.0002).

CONCLUSIONS

Result of our study suggested that Helicobacter pylori elicits different systemic humoral immune response in patients with gastritis and duodenal ulcer than in patients with gastric cancer and gastric lymphoma at least in intensity of stimulation of different immunoglobulin classes.